Aerobic exercise is a popular form of exercise that improves one's cardiovascular health by reducing blood pressure and providing other benefits to the human body. Aerobic exercise generally involves low intensity physical exertion over a long duration of time. Typically, the human body can adequately supply enough oxygen to meet the body's demands at the intensity levels involved with aerobic exercise. Popular forms of aerobic exercise include running, jogging, swimming, and cycling, among others activities. In contrast, anaerobic exercise typically involves high intensity exercises over a short duration of time. Popular forms of anaerobic exercise include strength training and short distance running.
Many choose to perform aerobic exercises indoors, such as in a gym or their home. Often, a user will use an aerobic exercise machine to perform an aerobic workout indoors. One type of aerobic exercise machine is a treadmill, which is a machine that has a running deck attached to a support frame. The running deck can support the weight of a person using the machine. The running deck incorporates a conveyor belt that is driven by a motor. A user can run or walk in place on the conveyor belt by running or walking at the conveyor belt's speed. The speed and other operations of the treadmill are generally controlled through a control module that is also attached to the support frame and within a convenient reach of the user. The control module can include a display, buttons for increasing or decreasing a speed of the conveyor belt, controls for adjusting a tilt angle of the running deck, or other controls. Other popular exercise machines that allow a user to perform aerobic exercises indoors include elliptical trainers, rowing machines, stepper machines, and stationary bikes to name a few.
One type of treadmill is disclosed in U.S. Pat. No. 4,151,988 issued to Herman G. Nabinger. In this reference, an apparatus for retarding the momentum of a treadmill includes a flywheel operatively associated with the belt of the treadmill, a brake arranged to move into and out of engagement with the flywheel and a manually operated lever for operating the brake whereby a person on the treadmill can, at his or her option, retard or stop the motion of the treadmill. Other exercise machines are disclosed in U.S. Pat. No. 8,876,668 issued to Rick W. Hendrickson; European Patent Application No. EP1188460 issued to Gary E. Oglesby; WIPO Publication No. WO/1989/002217 issued to William Lindsey; and U.S. Patent Publication No. 2002/0103057 issued to Scott Watterson.